Chelsea took a grip on Champions League Group E on a night when they announced a positive coronavirus test for Kai Havertz, the £72m signing from Bayer Leverkusen. They were helped by a pedantic VAR penalty decision that also resulted in a Rennes red card. It was an occasion that encapsulated the challenges and bitter frustrations of football in 2020. Timo Werner had already scored once from the spot and the Rennes left-back, Dalbert, been booked for the concession when there came one of those depressing and head-scratching moments that feels so typical of the modern game. Tammy Abraham had a shot blocked just inside the area by Dalbert in the 37th minute and nobody seemed too fussed about it. But then came the forensic investigation by VAR, which spotted that the ball had hit Dalbert’s shin and reared up to catch his arm, which he had accidentally raised a little too high. In the digital eyes of the law, it added up to another penalty and, even more heartlessly, a second yellow card for Dalbert. Werner scored again and Rennes, who are competing in Europe’s elite tournament for the first time, were broken. Chelsea had not played with any fluency in the first half but, equally, they had been untroubled at the back. The former would change after the break and the latter did not as the club’s new goalkeeper, Edouard Mendy, previously of Rennes, was able to enjoy a sixth clean sheet in seven matches. Mendy had only one save to make – from a shot by the Rennes substitute, Clément Grenier, in the 84th minute – but he made it, diving to push the ball away and, having been quiet all evening, it spoke volumes for his concentration levels. What a difference Mendy has made to the Chelsea defence and the same can be said of another new signing, Thiago Silva, who again oozed authority at centre-half. Over at right-back, Reece James had an encouraging game and it was his cross that teed up Abraham for the third goal. Frank Lampard reported that Havertz’s positive test had shown up on Monday and the result was confirmed by a second one on Tuesday. Every other Chelsea player tested by Uefa was negative. “Kai had minor symptoms on Tuesday and they have escalated slightly but he is fine,” Lampard said. “He’s at home, isolating. He’s doing the right thing. It’s one of those things in the modern day.” Havertz will miss Chelsea’s home game with Sheffield United on Saturday plus Germany’s matches during the international break and the episode offered the latest reminder of our turbulent times not to mention the unexpected obstacles to selection that managers must face. Lampard wanted an early tonic on the pitch and he got it as Werner’s movement inside the area proved too slippery for Dalbert. The Brazilian lunged in to tackle him, believing he could get to the ball first. He was wrong. Werner felt the contact and went down before picking himself up to open the scoring. The first-half featured little by way of attacking invention, although Hakim Ziyech did conjure a lovely piece of skill in the ninth minute, taking a touch and unleashing a volley from the edge of the area. He saw it dip narrowly over the crossbar. Rennes were neat and proactive for long spells, although they were unable to locate any cutting edge. They argued at 0-0 that Naif Aguerd’s header had hit Zouma’s arm inside the area, even though the Chelsea defender was turning away and seemingly oblivious to the connection, but there was no action from the referee or his VAR. The officials were clearly saving themselves and after the second penalty-second yellow card fiasco, Rennes’s players departed for the interval shaking their heads and nursing a sense of injustice. Werner’s second conversion, lashed high into the net, was his seventh goal in Chelsea colours. He has taken over as the penalty taker after two recent misses by Jorginho. “The penalty taking was not an easy decision,” Lampard said. “I had a conversation with Jorginho and his answer was professional. Timo took them very emphatically and I’m very happy with that.” Werner added: “I’m happy Jorgi is cool with it. It shows no one is selfish in the group.” Abraham’s finish was a beauty, touched home deftly at the near post, and Chelsea should have had more in the second-half. Ziyech lifted a half-volley high at the back post, Werner was denied when Damien Da Silva touched James’s cross away from him and the substitute, Olivier Giroud, spurned a one-on-one. The game, however, had long since been disfigured and Lampard offered his sympathy over the second penalty and red card. “If I was the manager of Rennes, I would not be happy,” he said. “It [the rule] is what it is in Europe.”